Adapter fitting for anesthetic administering circuits



W. W. HAY

June 27, 1961 ADAPTER FITTING FOR ANESTHETIC ADMINISTERING CIRCUITSFiled Dec. 23, 1958 2 Sheets-Sheet 1 WAYNE W. HAY

W .7 ATTORNEY 8. AGENT W. W. HAY

June 27, 1961 ADAPTER FITTING FOR ANESTHETIC ADMINISTERING CIRCUITSFiled Dec. 23, 1958 Sheets-Sheet 2 INVENTOR. WAYNE W. HAY

bzgm f7 ATTORNEY & AGE NT United, States Patent 015 ice Patented June27, 1961 2,989,960 ADAPTER FITTING FOR ANESTHETIC ADMINIS'DERINGCIRCUITS Wayne W. Hay, Madison, Wis., assignor to Air Reduction Company,Incorporated, New York, N.Y., a corporation of New York Filed Dec. 23,1958, Ser. No. 782,584

Claims. (Cl. 128188) This invention relates to adapter fittings used toconnect conduit elements in anesthetic circuits for administeringanesthetic gases and vapors by inhalation. More particularly, theinvention concerns improvements in socalled Y-adapters employed inclosed anesthetic circuits to provide a connection between theinhalation and exhalation conduits of the circuit and an inhaler devicethrough which a patients respiratory gases are breathed.

In a closed type anesthetic circuit, the patients exhalation gases arecirculated through an absorbent to remove carbon dioxide and'thence arereturned to the patient for reinhalation. The absorber portion of thecircuit is customarily provided with separate, flexible conduits leadingto and from the absorber which are attached to a suitable inhaler devicesuch as a catheter or a face mask. Check valves are located in therespective exhalation and inhalation sides of the circuit to cause thegases to move progressively through the circuit and thence return to thepatient. The Y-adapter is provided to facilitate the connection of theanesthetic circuit elements to the inhaler and also desirably serves toreduce or minimize the dead space or volume common to the inhalation andexhalation portions of the circuit which constitutes a volume of gasesin the circuit that is not circulated through the absorber andrepresents an inefliciency in the respiratory exchange obtain able inthe system. It is conventional, in such circuits, to administer make-upoxygen in amounts suflicient to replenish the oxygen consumed by thepatient and to introduce, in any suitable fashion, anesthetic vapors orgases which are inhaled by the patient to maintain a desired depth ofanesthesia.

Due to the complexities of modern surgery and the numerous specializedsurgical procedures now in common practice, it is desirable that theclosed circuit be capable of use under specialized surgical proceduresand, at the same time, permit a maximum degree of flexibility in thepositioning and arrangement of the physical elements of theadministering equipment. For this reason, it has been felt that anadapter having the respective connections for the flexible conduitsrelatively adjustable to one another would be advantageous. It is alsodeemed desirable to provide such an adapter through which the opening orconnecting element from the adapter to the patient inhaler might bedirectly visible to the anesthetist while in use so that the conditionand physiological behavior of the patient while under anesthesia couldbe more readily observed. Thus, for example, vomiting or the dischargeof mucus have frequently interfered with the proper breathing of thepatient by entering the inhaler or adapter inadvertently and Without theknowledge of the anesthetist so as to block the free exchange ofrespiration gases. Means enabling the anesthetist to directly oberve theinterior of the Y-adapter passages and connection to the inhaler willgreatly assist in overcoming such occurrences.

It is also desirable in a number of situations, and is preferred by manyanesthetists, to arrange the respective inhalation and exhalation checkvalves of the anesthetic circuit directly in the Y-adapter. Adequateprovision is necessary to permit the anesthetist to observe that thecheck valves are functioning properly, particularly when the valves arelocated in such close proximity 2 to the region accessible to thedischarged vomitus of mucus. Allowing visible inspection of the'interiorof the Y-adapter may additionally afford a means for the desiredinspection of the check valves disposed within the Y-adapter.

In some instances, portions of the Y-adapter have been made of atransparent plastic material which makes it possible for the anethetistto inspect the interior of the adapter for the purposes indicated above.However, such transparent materials are nonconductive and withoutfurther provision amount to the insertion of an insulating memberbetween the inhaler, whichis conventionally either metallic or ofconductive rubber construction, and the tubular breathing conduits whichsimilarly are of electrically conductive construction and conventionallygrounded by a suitable electrically conductive means to avoid theaccumulation of static electric charges in the anesthetic circuit. Suchstatic charges are well recognized as a potential hazard which, uponrapid discharge, may cause explosive detonation of the anestheticmixtures within the circuit. Consequently, it is standard practice toutilize, in anesthetic apparatus, elements or other means which furnisha completely electrically conductive path so that such charges may notbe accumulated. It has, therefore, been a significant problem to furnisha Y-adapter having a transparent construction as indicated above whichadequately overcomes the problem of electrical conductivity and which,at the same time, affords a high degree of flexibility for thearrangement and orientation of the connections for the respectiveconduit elements of the circuit and which, at the same time, permits aconvenient location of the inhalation and exhalation check valvestherein. In addition, there is the further problem in the provision ofsuch a type of Y-adapter of constructing such an adapter in a mannerpermitting it to be readily dismantled for thorough cleaning andsterilization for continued use.

Accordingly, it is an object of the present invention to provide animproved adapter for anesthetic administen'ng apparatus forming anadjustable connection between an inhaler and the inhalation andexhalation conduits of an anesthetic circuit.

A further object of the present invention is to provide a Y-adapter foranesthetic apparatus having a barrel portion of substantiallytransparent construction provided with means for connection thereof withan inhaler and relatively adjustable end pieces carried thereon adaptedto receive anesthetic circuit conduits.

A further object of the invention is to provide a Y- adapter such asthat indicated above having a post member extending through said barrelportion interconnecting the relatively adjustable end pieces and whereininhalation and exhalation check valve means are carried thereon.

It is a still further object of the present invention to provide aY-adapter for anesthetic administering apparatus having a central barrelportion arranged for connection with an inhaler, relatively adjustableend pieces supported thereon and resilient means interposed between saidinhaler and the adjustable end pieces for maintaining an electricallyconductive path between the inhaler and the adjustable end pieces.

Other objects and advantages of the present invention will become moreapparent by reference to the following description of a preferredembodiment thereof and the accompanying drawings in which:

FIG. 1 is a side elevation view partially in section showing a Y-adapterin accordance with a preferred embodiment of the present invention,seated in a face mask and illustrating the adjustable end pieces of theadapter in relatively rotated positions;

FIG. 2 is a plan sectional view taken substantially along the line 2-2in FIG. 1 looking in the direction of the arrows, with the end piecesshown in the same plane;

FIG. 3 is a partial sectional view taken substantially along the line3-3 in FIG. 1, with the securing means and valve elements removed,showing the means for connecting theY-adapter to the face mask andillustrating in greater detail resilient, electrically conductive meansinterposed between the inhaler and the end pieces;

' FIG 4 shows the metallic bushing element providing the resilientconnector means of FIG. 3 in an exploded view; V v

FIG; 5 is an end view of the inhalation check valve with the disc valveelement thereof partially broken away;

FIG. 6 is a plan sectional view taken substantially along the line 66 inFIG. 3 looking in the direction of th arrows;

FIG. 7 is an enlarged partial sectional view illustrating in greaterdetail the securing means for holding the adjustable portions of theY-adapter in assembled relation; and

FIG.'8 is a sectional view showing a detail of construction of thesecuring means taken substantially along the line 88 in FIG. 7 lookingin the direction of the arrows.

Referring to FIG. .1, Y- adapter is shown generally at 10 which includesa central barrel portion, or hub, 12 having at the opposite ends thereofrelatively rotatable end pieces, or nipples, 1 4 and 16 to which areconnected, respectively, the'ends of flexible corrugated conduits 18 and20. A tubular extension 22 of the central hub 12 forms a nippleconnector having an opening 23 which communicates with a face mask shownat 24. The face mask is provided with a cylindrical opening 25 in whichthe connector 22 of the adapter is received. A metal hook-ring 26 issecured on the upper part of the mask body as is well known to permitthe mask to be held securely in place against the face of the patient bymeans of an elastic head band. A relief valve shown at 28 is arranged inthe hub portion of the Y-adapter in communication with the chamber 12therein, seen in FIG. 2, and operates to relieve the pressure within theanesthetic breathing circuit in the event the pressure level thereinrises above a predetermined value. It will be understood that thecorrugated hose conduits 18 and 20, seen in FIG. 1, may be connected toother devices, including, for example, a carbon dioxide absorber andother accessories, through which the respiratory gases are conducted, toform a conventional closed anesthetic circuit. The circuit is not shownand need not be described in'detail Since such expedients will be wellknown and understood to those skilled in the art.

' The barrel portion 12 of the adapter may be made of a transparentplastic material such, for example, as a clear cellulose, acetate,butyrate polymer so that the inner central chamber 12' is visiblethrough the walls thereof. 'The ends of the central barrel portion ofthe adapter are recessed at 29 to provide openings for receiving thematching cylindrical faces of the end pieces 14 and 16 as may best beseen in FIG. 2. The end pieces are held in assembled relation with thebarrel portion of the adapter by a central elongated stem 30 which isrigidly seated in a cylindrical receptacle 32 in the end piece 16 andsecured at its opposite threaded end 34 by a retaining nut designatedgenerally by the numeral 36, bearing against the opposite end piece 14.The arrangement of the retaining nut may best be seen in FIG. 7. The endpiece 14 is provided with a cup-shaped cavity 38, the inner wall ofwhich is provided with an opening 40 through which the threaded end 34of the retaining stem protrudes. The retaining nut 36 has an internallythreaded barrel portion 42 that may be threaded along the length of thethreaded end of the stem 34. A selfretaining washer member 44 is carriedon the barrel portion 42 of the retaining nut and is retained thereon bythe inwardly crimped end '46 so that the washer is rotatable relative tothe retaining nut. The opening 48 in the washer is not circular but hasparallel sidewalls shown at 48 in FIG. 8 which correspond to theopposite milled faces 34' formed at the threaded end 34 of the retainingstern. Such construction prevents the rotation of the washer 44 relativeto the retaining stem but permits relative rotational movement of theretaining nut 36 required for longitudinal movement thereof in ordertosecure the assembled parts of the adapter. In this arrangement, thewasher 44, upon tightening of the retaining nut is urged thereby againstthe bottom face 38' at the bottom of the cup-shaped depremsion 38 in theend piece 14. By such inward threading of the retaining nut, it can beseen that the end pieces 14 and 16 are clamped and thus secured againstthe opposite ends of the central barrel portion of the adapter. Theretaining nut may be threaded sufficiently that the pressure producedagainst the end pieces will retain them against relative rotationaladjustment under normal forces exerted on the adapter during use. Inorder to adjust the angular position of the end pieces, the retainingnut preferably is slightly loosened. Alternatively, the retaining nutmay be tightened to a slightly less degree to permit manual adjustmentof the end pieces without loosening the nut. It can be seen that therotation of the retaining post produced by relative angular adjustmentbetween the end pieces 14 and 16 of the adapter will not tend to afiectthe setting of the retaining screw 36 inasmuch as the retaining screwmoves as a unit with the retaining stern and the frictional eifectsexerted throughthe end piece 14 are absorbed by the intermediate washer44 that is mechanically linked with the central stem. Thus, the washerand retaining nut do not have relative rotation during manipulation ofthe end pieces. Relative angulations of the end pieces consequently willnot result in unthreading the screw and possibly allowing eventualcomplete separation of the adapter parts such as might otherwise bepossible.

The chamber 12 within the central portion of the adapter is separatedfrom chambers 50 and 52 in the end pieces, respectively, by inhalationand exhalation check valve units shown at 54 and 56. The check valveunits are of identical construction and are arranged with respect to oneanother in the usual manner so that inhalation valve 54 opens into thechamber 12' allowing the gases to be drawn into the chamber when thepatient inhales, and so that exhalation valve 56 opens from the chamberallowing discharge of gases therefrom when the patient exhales. Each ofthe valve units includes a central collar 58 which is slidably receivedon the retaining stem 30. An annular rim 60 extends concentrically aboutthe central collar and is connected therewith by a plurality of radialspokes 62 that are best seen in FIG. 5. A radial flange 63 projectsoutwardly from the rim and is received at the bottom of'the recess 29where it is compressed between the central body portion, or hub, 12 ofthe adapter and the rotatable end pieces to form a gas-tight seal. Therim of the valve units also extends longitudinally with respect to thecentral collar and is tapered to provide an annular valve seat 64against which a valve disc 66 is adapted to be seated. The valve disc ispreferably made of a thin, flexible material such as rubber and has anopening at its center which is stretched over the retaining stem 30 sothat the outer edge of the disc is free tomove toward or away from thevalve seat 64 in" response to the patients breathing. The disc valveelement 66 can be moved along the length of the retaining stem 30 to thedesired position relative to the annular valve seats 64. It may be seenthat the abutment of the collar 58 of the exhalation check valve againstthe cylindrical receptacle 32 for the retaining stem serves to orientthe inner end of the disc valve of the exhalation valve unit Similarly,the abutment of the collars 58 between the inhalation andexhalationvalves serves to orient the disc valve element of the inhalation checkvalve. The collars 58 terminate a slight longitudinal distince withinthe plane of the annular valve seat 64 so thatwhen the' central portionsof the valve discs are oriented as shown in the drawing, the discs willbedeflected slightlywith respect to'the centers thereof causingthem tobe undera slight seating stress against the respective valve seats. Itwill beunderstoodthat it is desirable, in breathing check valves of thistype, to produce a slight seating stress which will prevent back flowthrough the respective check valves .but which, at the same time, willnot produce any noticeable interference'with the patients respiration.

A further feature of the check. valve units 54'and 56 involves thearrangement of the collar portions 58; with respect to the radial flangeportions 63 such that" the valve units cannot inadvertently be mountedincorrectly within the adapter. This is obtained by locating the annularrim 60 toward one end of the collar 58 such that it 'is not symmetricalwith respect t'o'the length thereof. When the check valve units areplaced on the retaining stem 30 as shown in the drawings; duringassembly of the adapter, 'it will be seen that the end piece16 is freeto'be placed within the corresponding recess 29 and that similarly theend piece '14 is free to be receivedin the opposing recess. The assemblymay then be secured in the desired manner by tightening the retainingnut 36 as previously described. On the other'haud, if it be assumed thatone or the other. of the check valve units or both of them have beenplaced on the stem 30 in the reverse direction, it will be seen thatthedifferent spacing between the flanges 63 and the projecting ends'of thecollars 58 will produce an interference between one or both of the endpieces and the central hub preventing their being seated in the usualmanner. This 'will, of course, call immediate attention to the incorrectarrangement of the valve units so that it may be rectified without therisk of harmful effect to the patient. It may be seen, if no suchsafeguard were provided against inadvertent reversal of either of thecheck valves, that the patient might be prevented from inhaling orexhaling upon application of the breating apparatus to the patient.

As mentioned above, the central body portion 12 of the adapter is of atransparent plastic material that is electrically nonconductive andwhich consequently forms an insulation with respect to the conduction ofelectrical charges between the rotatableend pieces 14 and 16 carryingthe conductive conduits 18 and 20 and the face mask 24 which, aspreviously mentioned, is either normally made of a suitable conductiverubber material or is otherwise rendered sufiiciently conductive toallow dissipation of static charges that may be imparted thereto. Thisdifiiculty is overcome in the present device by the provision of ametallic bushing shown at 70 in FIG. 1 forming a sheath, or sleeve,carried on'the tubular connector nipple 22 of the adapter which isseated in the face mask. It will be seen that the metallic bushingincludes a longitudinal portion seated within the mask opening 25 thatis in intimate contact with the surrounding wall of the mask. At theupper end the bushing hasa radial flange 72 which is more easily seen inFIGS. 3 and 4 from which a pair of prongs 74 and 76 extend up-' wardly,longitudinally of the bushing. The outer diameter of the flange 72corresponds substantially to the width of the central body portion, orhub, .12 of the adapter so that the edge of the flange 72 coincidessubstantially with the flat end face of the hub: In each of the endfaces, a vertical recess 78 is formed which is slightly 'wider'than thewidth of the prongs 74 and 7 6. The recesses 78 are adapted to receivethe prongs when the bushing 70 is placed over the tubular connectorportion 22. As shown in FIG. 3, the tubular prongs 74 and 76 have beendepressed and are positioned substantially within their respectiveaccommodating recesses 78. The

. 6 recesses are not readily visible in this sectional view. The prongs74 and 76 initially are bent outwardly slightly from the'a'ccess ofthe'bushing asindicated in FIG. 4 and as shown by the dotted lines inFIG. 3. The dotted lines show the positionsfofthe prongs before the endpieces 14 and 16 of the adapter are assembled. When, however,l the' end:pieces are'inse'rted in the receiving recesses}? at the opposite facesof the central hub of the adapter andsecu'red thereagainst, ashereinabove described, the'shoulders 80 and 82 respectively, which areformed 'odthe 'confrontingffaces of the end pieces 14 and "1 6j,. bearinwardly againstthe diverging prongs 74 and'76 and press" them inwardlyto the positions shown in 3. .In these positions, of course, the prongsare deflected from their normal divergent configuration creating "a:stress m'thinthe prongs which resiliently urges theprongs outwardly tomaintain contact'thereof with the confronting shoulders of therespective end pieces. Thus, when the collar70 is assembled 'on thecentral body portion of the adapter as shown, and the end pieces aremounted therein in the usual'manner, the prongs 74 and 76" maintain a.resilient contact between the end pieces and the bushing affording acontinuous electrical conductive path between the end pieces and theface mask. The

prongs, of course, continually bear against the shoulders 8'0'and 82ofthe end-pieces throughout all angular positions of the end pieces}Such an electrically conductive path, of course, is also provided if theadapter in connected instead with a catheter or other inhaler device, inwhich case the adapter nipple, provided with an interposed' conductiveelement such as the sheath 70 will similarly-maintain a conductive pathbetween the sheath and the adjustable vend pieces. It is preferable toconstruct the bushing 70 such that it is a press fit on the tubularconnecting portion 22 of the adapter so that it will be self-retainingthereon and nonsusceptible to inadvertent separation therefrom.

It is apparent from the preceding description that a highly advantageousadapter device for anesthetic circuits is provided in accordance withthe present invention which affords a high degree of flexibility ofadjustment; furnishes visibility of the interior portions of the conenector while at the same time not interfering with the desiredcontinuity of an electrically conductive path be tween the inhalerdevice and the remaining portions of the anesthetic circuit that areproperly and adequately grounded; and which enables the disposition ofthe check valves in a simple and convenient manner in the adaptersubject to visual inspection. The invention, of course, is not limitedto the specific embodiment herein described but may be used in otherways without departure from its spirit as defined by the followingclaims.

I claim:

1. An adjustable connector for anesthetic administering circuitscomprising a housing having a breathing chamber therein and an openingadapted to be placed in communication with an inhaler, said housingincluding at least. a portion thereof which is transparent to enablevisual inspection of said breathing chamber, relatively adjustableconnector means having passages communicating with said breathingchamber adapted to receive gas conduits thereon for circulating gas toand from said chamber, and means resiliently engaging at least one ofsaid-relatively adjustable connector means adapted to contact an inhalerplaced in communication with said opening of said breathing chamber,efiective to maintain an electrically conductive path therebetween.

2. In a Y-adapter forinhalent anesthetic administering apparatus, a bodydefining a breathing chamber having a transparent wall portion,connector means forming a gas passage communicating with saidbreathing'chamber adapted to form a gas connection with an inhaler,inlet and outlet fittings adjustably mounted on said body havingcorresponding passages communicating respectively '7 with said breathingchamber, electrically conductive contact means forming a part of saidconnector means, and resilient means forming an electrically conductiveconnection between said electrically conductive contact means and atleast one of said fittings.

3 ha Y-adapter for inhalant anesthetic administering apparatus having aconnector adapted to be connected with an inhaler and relativelyadjustable conduit fittings adapted to receive gas conduit means,electrically conductive contact means forming a part of'said connectoradapted to form an electrical contact with inhaler means and resilientmeans forming an electricallyconductive path between said contact meansand said adjustable conduit fittings.

4. An adapter fitting for anesthetic administering apparatus adapted toprovide a gas connection between inhalation and exhalation conduits ofan anesthetic breathing circuit and an inhaler comprising a body portiondefining a breathing chamber and having a connector including a passagecommunicating with said chamber adapted to be connected with an inhaler,adjustable conduit fittings separably mounted on said body portionadapted to receive thereon, respectively, inhalation and exhalationconduits of a breathing circuit :haw'ng corresponding passages thereincommunicating with said breathing chamber, electrically conductivecontact means carried on said connector of said body portion arranged toform an electrical contact with an-inhaler received thereon andresilient means compressed by at least one of said separable conduitfittings forming a part of said electrical contact means biased so as tomaintain engagement with said conduit fitting throughout the range ofadjustment thereof.

5. A Y-adapter for inhalant administering apparatus comprising a centralhub having a breathing chamber therein opening in opposite end faces ofsaid hub, means forming a connector adapted to be connected with aninhaler having a gas passage communicating with said breathing chamber,corresponding end pieces adjustably secured against the opposite endfaces of said hub hav ing gas passages therein respectivelycommunicating with said breathing chamber which are adapted to receiveinhalation and exhalation conduits respectively of an anestheticbreathing circuit, detachable retaining means including an elongatedstem extending between said end pieces through said hub having anadjustable portion externally accessible to permit said end pieces to beadjustably secured against the opposite end faces of said hub andinhalation and exhalation check valve-.means,-re-.

spectively, carried by said elongated stem of said retaining means atspaced intervals along the length thereof, and arranged within saidadapter to separate said breathing chamber from said passages of saidadjustable end pieces.

6. A Y-adaptcr for inhalant administering apparatus comprising a centralhub having a breathing chamber therein opening in opposite end faces ofsaid hub, means forming a connector adapted to be connected with aninhaler having a gas passage communicating with said breathing chamber,corresponding end pieces adjustably secured against, the opposite endfaces of said hub havinggas passages therein respectively communicatingwith said breathing chamber which are adapted to receive inhalation andexhalation conduits respectively of an anesthetic breathing circuit,detachable retaining means extending bet ween said end pieces throughsaid hub having an adjustable portion externally accessible to permitsaid end pieces to be secured against the opposite end faces of said huband inhalation and exhalation check valve means respectively carried bysaid retaining means and arranged within said adapter to separate saidbreathing chamber from said passages'of said adjustable end pieces, saidretaining 'means' including an elongated'stem secured in one of said endpieces and protruding through said other end piece, said externallyaccessible securing means including a nut threadedly received on saidprotruding end of said stem and said check valve means each'including asleeve member slidably received on said stem between said end pieces andhaving radially spaced annular rim port-ions compressed between saidrespective end faces ofsaid hub and said corresponding end 7.A.Y-adapter according to claim 6 'wherein said annular rim portions ofsaid checkv-alve means are dis posed nonsymmetrically with respect tothe lengths of said sleeve members such that said end pieces may besecured in said hub in only asingle predetermined orientation of saidcheck valve means.

8. A Y-adapter in accordance with claim 7 wherein said hub includes atransparent wall portion.

9. A Y-adapter for inhalant anesthetic administering apparatuscomprising a central hub constructed of a substantially transparentelectrically nonconductive'material, said hub defining a breathingchamber therein opening at opposite substantially parallel end faces ofsaid hub, a cylindrical protrusion extending outwardly from said hubadapted to be connected with an inhaler including electricallyconductive contact means thereon adapted to be placed in electricalcontact with an inhaler connected therewith, corresponding end piecesrotatably received respectively against the opposite end faces of saidhub having gas passages therein communicating respectively with saidbreathing chamber, retaining means extending between said opposite endpieces through said hub adjustable to tighten said end pieces againstthe opposite end faces of said hub, inhalation and exhalation checkvalve means carried on said retaining means disposed respectively toseparate said breathing chamber from the gas passages in said end piecesand resilient means forming apart of said electrical contact meansextending upwardly contiguously with said end faces of said hubdeflected by said end pieces so as to produce a stress under which saidresilient means is biased toward said end pieces to frictionalengagement therewith throughout the rotated adjustments of said endpieces.

10. A Y-adapter for inhalant administering apparatus comprising acentral hub having a breathing chamber therein opening in opposite endfaces of said hub, means forming a connector adapted to be connectedwith an inhaler having a gas passage communicating with said breathingchamber, corresponding end pieces adjustably secured against theopposite end faces of said hub having gas passages therein respectivelycommunicating with said breathing chamber which are adapted to receiveinhalation and exhalation conduits respectively of an anestheticbreathing circuit, detachable retaining means vextending between saidend pieces through said hub having an adjustable portion externallyaccessible to permit said end pieces to be secured against the oppositeend faces of said hub, valve seat means defining a valve openingseparating said gas passages in said end pieces from said breathingchamber, said detachable retaining means extending through said valveopenings in fixed spacial relation thereto, and separate valve elementscarried on said retaining means disposed in operative relationship toeach of said valve seat means to coact therewith to alternatelyopen inresponse to breathing and thereby place said breathing chamber incommunication with one or the other of said end pieces during inhalationand exhalation.

References Cited in the file of this patent UNITED STATES PATENTS

